Question
why do the leaves at bottom of plant turn yellow?

Answer
Hi Gary,
Thanx for your question.  There are a number of reasons for the bottom leaves of the Stella d'oro daylily to turn yellow.  Too much water, not enough water, too much fertilizer (maybe seepage from lawn fertilizers that are high in nitrogen...).  If the rest of the plant is healthy, it could be just old leaves or if the plants are too close or crowded.  Daylilies should be lifted and separated every three years otherwise, they will crowd themselves out and reduce flowering and become a hotbed for disease.

By the way, Stella d'oro means Gold star, hence the name of the day lily.  I hope this helps.

Tom